Maybe it's the jealousy of seeing another fighter being thrusted, or the lure of yet another challenge?

To some degree, it's probably all of the above. And in Manny's case, there's new wrinkle which is addressed below.

Regardless the reason, popular, top fighters seem unable to resist the temptation to return to the ring.

Some may ask: How many boxing stars have unretired?

But the real question is, or should be: How many starsnever returned after retiring the first time?

Manny Pacquiao and public service

Manny insists he wants to leave boxing because he intends to serve in the senate, and dedicate his passion for public service full time.

His heart is as big as all of the Philippines and regardless of his (alleged or misunderstood) views on certain issues, he should be commended.

Should Manny win a senate seat, however, he'll learn bureaucracy can often be a slow, bumpy road to change. So, don't be surprised if the day-to-day miniusa bores him.

Pacquiao will realize, if he hasn't already done so, he can make a bigger, faster impact on issues he cares for by fighting and earning sums of money, much of which can be donated to worthwhile causes.

Moreover, his recent controversial comments prove he doesn't have to be in the senate to make a big splash.

Retirement prediction: Look for Pacquiao to retire after the Bradley fight only to unretire 12 to 24 months later.

That will be just enough time for him to get a little bored and really miss boxing. Also, people will have forgotten and/or forgiven him for his comments by then. Moreover, from a promotional standpoint, he'll be hot because the boxing world will have started to miss him.

Top Rank will bill his comeback fight as 'The Pride of the Philippines Returns' and it will be massive.

Look for Manny, after a year or two away, to stage 1 to 3 bouts. If they start him with a tune-up and Manny looks good in that bout, his second fight will be absolutely massive if the opponent is a star as well.

... Only after that will Manny fully dedicate himself to public service and never look back.